KOT.CASH

Technical architecture

• 233 TypeScript/TSX files, 60+ API routes, 17 MongoDB models
• 7 continuously running PM2 workers (Next.js server + 6 background processes)
• Nginx as a reverse proxy with SSL/TLS (Let’s Encrypt), rate limiting and server-version hiding
• A monolithic Next.js architecture with server/client separation following React 19 Server Components

Exchange Engine — three exchange modes

Integration with the Easybit API (liquidity provider).

• Simple Swap — float (1%) and fixed (1.5%) rates, 250+ coins, instant quote, QR payment, tracking via Blockchair, guest exchange without registration.
• Multi-Hop (custom implementation) — an automatic 2-step exchange through bridge wallets; a PM2 worker runs the hop1 → hop2 chain in the background, unlocking pairs that have no direct market.
• Split Swap (custom implementation) — exchanging a single amount into 2–4 coins with configurable shares, a 3–5% fee, and a dedicated execution and monitoring worker.

Account area

• Registration / login / password recovery via email tokens
• TOTP 2FA (Google Authenticator, otplib + qrcode)
• History of all exchanges (regular + multihop + split) in a single interface
• Email change with confirmation, avatar upload, referral-code linking

Admin panel

A fully featured back office at a hidden URL.

• Dashboard with statistics (all time / 30d / 7d / 24h), revenue and charts
• Transactions with filters, detail pages and CSV export
• Users, referral links with statistics, tickets and a live online chat
• IP Blacklist and TOTP-protected admin login

SEO infrastructure

• 292 static pages (EN + RU mirror): blog, 31 pair pages, 53 country pages
• hreflang, JSON-LD Schema.org, canonical, sitemap, robots.txt
• IndexNow — instant URL submission to Bing/Yandex/DuckDuckGo on publish
• URL-based i18n (EN on /, RU on /ru/), Google Analytics GA4

Security

• Content Security Policy and rate limiting at the nginx level (separate zones)
• JWT in an httpOnly cookie, bcrypt, TOTP 2FA for admin and users
• Blocking of common attacks (.php, .env, .git, wp-admin), one-year HSTS
• Validation via Zod and a custom sanitize, a worker secret for internal APIs

Integrations

Telegram automation

• Promo bot (@kotcashnews) — a daily post at 10:00 MSK with rates, a cat-themed tone of voice, rotating copy, ref links
• Chat bot (@kotcashchat) — interactive /rate BTC from the site widget in real time, long-polling

Design and UX

• Dark/light theme, 3D CSS animations, a live Rate Ticker and Rate Sparkline
• Styled QR codes, country flags, skeleton loading, mobile-first
• A demo worker generates a realistic stream of “completed exchanges” to showcase activity

Infrastructure

• Ubuntu Server, Nginx (SSL, rate limiting, static files)
• PM2 cluster: kot-cash + multihop / split-swap / promo / chat / news / demo workers
• MongoDB (local, ~21K rate_snapshots), email via Dovecot + Roundcube through a relay